Chain guide mounting assembly for the reduction of chain induced noise and vibration in a chain driven overhead cam internal combustion engine

A chain guide mounting assembly for an internal combustion engine having a crankshaft, an overhead camshaft, and a chain connecting said crankshaft to said camshaft, said assembly comprising:

• a chain tensioning device for applying tension on said chain to reduce chain slack therein, said device comprising:
• an elongate chain tensioning member having a first end, a second end opposite said first end and a chain support surface intermediate said first and second ends and having an elongate resilient member mounted on said chain support surface for supporting said chain, said first end being pivotal connected to said engine;
• and,
• a force application means engaging said second end such that when a force is applied by said force application means, said chain tensioning member pivots about said first end thereby applying a lateral force at said chain support surface on said chain that serves to reduce slack in said chain;
• an elongate chain guide member fastened to said engine by vibration isolation means, said chain guide member having a first end with a first bore for receiving a first vibration isolation means, a second end, opposite said first end, with a second bore for receiving a second vibration isolation means, a chain guide surface intermediate said first and second ends and having an elongate resilient member mounted on said chain guide surface for guiding said chain, and further having a vibration isolation means, with said vibration isolation means comprising:
• a first, substantially cylindrical resilient member comprising:
• i) an exterior side wall,
• ii) an axial bore through said member,
• iii) a flange portion at one end thereof, said first resilient member fitted within said first bore of said chain guide member such that an underside surface of said flange portion rests on a first outer surface of said chain guide member,
• iv) a frusto-conical annular recess about said bore at said flange portion end, and
• v) an annular recess in an underside surface of said flange portion near a boundary between said flange portion and said exterior side wall;
• a second, substantially cylindrical resilient member comprising:
• i) an exterior side wall,
• ii) an axial bore through said member,
• iii) a flange portion at one end thereof, said second resilient member fitted within said second bore of said chain guide member such that an underside surface of said flange portion rests on a second outer surface of said chain guide member, and,
• iv) an annular recess in an underside surface of said flange portion near a boundary between said flange portion and said exterior side wall;
• a rigid, substantially cylindrical sleeve in interference engagement within said bores of said first and said second resilient members such that a radial preload is applied to said first and second resilient members, said sleeve having a frusto-conical flange portion at one end thereof for bearing against the engine, said sleeve further having an axial length less that the length of said first and second resilient members when fitted within said bore of said chain guide member;
• a washer overlaying a top surface of said flange portion of said second resilient member;
• a fastener passing through said sleeve and said bores for fastening said chain guide member to said engine such that an axial preload is applied to said first and second resilient members when said chain guide member is mounted to said engine;
• and,
• wherein said first and second resilient members each comprise a material selected from the group consisting of a fluorinated hydrocarbon and a fluorosilicone.

A method of mounting a chain guide member to an internal combustion engine having a crankshaft, an overhead camshaft, and a chain connecting said crankshaft to said camshaft, said method comprising the steps of:

• forming a chain guide member with a chain guide surface for guiding said chain;
• fastening said chain guide member to said engine using vibration isolation means comprising the steps of:
• fitting a first, substantially cylindrical, resilient member having an exterior side wall, an axial bore therethrough and a flange portion at one end thereof within a bore formed in said chain guide member such that an underside surface of said flange portion rests on a first outer surface of said chain guide member;
• fitting a second, substantially cylindrical, resilient member having an exterior side wall, an axial bore therethrough and a flange portion at one end thereof within said bore of said chain guide member such that an underside surface of said flange portion rests on a second outer surface of said chain guide member;
• radially preloading said first and second resilient members by engaging a rigid, substantially cylindrical sleeve in an interference fit within said bores of said first and said second resilient members;
• and,
• fastening said chain guide member to said engine by passing a fastener through said sleeve and said bores.